Mar.9 (GMM) An inspection of McLaren's 2010 car has been deferred until Thursday, the day of official scrutineering for the season opening Bahrain grand prix at the Sakhir circuit.

FIA technical delegate Charlie Whiting accepted an invitation to visit the British team's Woking factory last Friday, following reports about the questionable legality of the MP4-25's rear wing design.

The issue had been brought to the public and media's attention by Red Bull's Christian Horner, who said Ferrari was also concerned.

But Whiting was unable to reschedule his McLaren visit after delays in the wake of a flight from Brazil.

It is believed the concerns about the wing relate to air channelled via the engine airbox above the drivers' heads through the 'shark fin' engine cover and exiting through a slot.

The innovation is believed to have contributed to McLaren's up to 6kph straight line speed advantage as seen at the final winter test in Barcelona.

Meanwhile, Germany's Auto Motor und Sport has brought attention to yet another unique innovation on the Mercedes-powered car, to be raced this weekend by Lewis Hamilton and Jenson Button.

Photos taken at the Barcelona test depict a small air inlet on the left-hand side of the upper monocoque, in front of the drivers' helmets.

The magazine speculates that Button and Hamilton may operate the intake, allowing or disallowing air to travel through the car and exit at the rear, by hitting a trigger with their left knees.